Protected spark-plug.



G. F. DAY.

PROTECTED SPARK PLUG.

APPLICATION FILED APR.12, 1910.

1,082,818, Patented July 16, 1912.

. i I, r it B 1 t X a d '1 vf B 51 s wiifieases Z?vertarr GEORGE F. DAY, OF WINTHROP, MASSACHUSETTS.

PROTECTED SPARK-PLUG.

Specification of Letters Patent.

Application filed April 12, 1910.

Patented July 16, 1912.

Serial No. 554,948.

To all whom it may concern:

Be it known that I-, Gnouen F. DAY, a citizen of the United States, and resident of \Vinthrop, in the county of Suflolk and State of Massachusetts, have invented new and useful Improvements in Protected Spark-Plugs, of which the following is a specification.

This invention relates to spark plugs for internal combustion engines and its object is to provide a protected spark plug, of novel and improved construction, constituting a unitary article completein itself, and substantially proof against water or moisture, which if admitted to the plug itself tends to short circuit the igniting circuit and interfere with the proper operation of the spark plug and consequently of the engine.

It is common knowledge that ordinary spark plugsfor internal combustion engines which are exposed to the elements, upon becoming wet or damp, frequently become short-circuited, with the result that the operation of the engine is seriously interfered with. This is particularly true of engines in motor boats, which are often exposed not only to rain and fog, but also in rough weather to spray and splashing from the waves. Moreover, ordinary spark plugs are exposed not only to the elements, but also to danger of injury or breakage by being struck by tools which are used about the engine, or by other things, since a comparatively light blow will oftentimes break or crack the projecting, exposed, porcelain core of the plug.

I am aware that it has been proposed to protect spark plugs under such conditions by covering them with hoods, but such devices so far as I am aware, have constituted merely independent attachments to be applied over spark plugs of ordinary construction, and have not constituted componentparts of the spark plug itself.

One of the principal objects of my nvention is to provide a protected spark plug which shall be a complete unitary article in itself, and applicable to the engine as aunit, as distinguished from an independent attachment to be applied as an extra part to a plug of ordinary construction.

The accompanying drawing illustrating the invention, is a vertical, central section of a protected spark plug embodying the invention.

A represents a plug core of insulating material such as porcelain through which extends the conductor a, the lower end of which constitutes the sparking point, and the upper or outer end of which is provided with the screw threaded binding post a, and thumb nut 64 for the leading-in wire. The core A is made with a flange or collar a by which it is held within the casing as hereinafter described. The casing comprises two separable members, namely, the bushing B adapted tobe screwed into an engine cylinder, and the gland member B screwed into the outer endof the bushing. The bushing B is provided with a shoulder b on its interior, and the core A is held in place by the two members of the casing, the gland member B clamping the collar a of the core between the end of the gland and said shoulder 6 The gland member B is integrally. extended outwardly at its outer end to form an enlarged protective wall B, constituting a protective chamber 0 surrounding the outer end of the core. The top of said chamber is closed by the removable cover D, screwed into-the end of wall B, thus forming a closed waterproof chamber covering and inclosing the outer end of the core. An aperture 1) is provided in the side of the casing B through which the leading-in wire passes, and a sleeve 1) of insulating material is secured in said aperture, preferably sloping downward as shown, so as to shed any water or moisture which lodges on the casing. The inner surface of the chamber C may be lined with insulating material (I, such as enamel.

I claim:

1. In a protected spark plug having a core with an integral collar adjacent its lower end, and a bushing inclosing the lower end of the core and provided with a shoul der for the reception of the.eollar, a gland engaging in threaded relation the upper end of the bushing about the core and having its lower end binding againstthe collar to hold the core within the bushing, said gland having an outstanding flange on its upper end, said flange being upturned inolfset relation to the gland about the exposed portion of the core, the flange being provided with an opening in one side for the passage of a lead wire therethrough, and a detachable cap closing the upper end of the flange. I

2. A protected spark plug comprising a core, a. bushlng inc-losing the lower end of the core, and a packing gland engaging the upper end of the bushing and being located about the core to bind the same in the bushing, said gland having an outwardly extendingannular flange at its upper edge, said flange being turned up in spaced relation about the exposed portion of the core to house the same, and having a 10 lateral opening for the introduction of a lead wire.

Signed by'me at Boston, Massachusetts this ninth day of April 1910.

GEORGE F. DAY. Witnesses:

ROBERT GUSHMAN, CHARLES D. WooDBERRy. 

